Problem: $ { \left[\begin{array}{r}{-2} \\ {-2} \\ {2}\end{array}\right]+\left[\begin{array}{r}{3} \\ {3} \\ {-1}\end{array}\right] = {?} } $
To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{r}{-2}+{3} \\ {-2}+{3} \\ {2}+{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{r}{1} \\ {1} \\ {1}\end{array}\right]}$